EP0113669A2 - Cylinder for intaglio printing presses - Google Patents

Abstract

In the case of a cylinder for gravure printing machines with a device for tensioning winding plates (11), which has a clamping piece (5) which can be pivoted about the cylinder axis and has an outer contour corresponding to the outer cylinder contour, this allows an exact cylindrical contour of the winding plate (11) to be clamped on the Cylinder circumference and at the same time a small clamping path in the circumferential direction ensure that the clamping piece (5), which can be pivoted about the cylinder axis, has an additional beak edge (8) which can be pivoted about an axis (15) offset parallel to the cylinder axis (2) and cooperates with a clamping member (22) has an associated hanging claw of the winding plate (11).

Description

The invention relates to a cylinder for gravure printing machines with a device for tensioning winding plates, which has a clamping piece which can be pivoted about the cylinder axis and has an outer contour corresponding to the cylinder outer contour.

In the known plate clamping devices of this type, a comparatively large pivoting angle of the clamping piece, which can only be pivoted about the cylinder axis, is required in order to be able to bring the angled or profiled plate ends into and out of engagement with the front edge of the clamping piece in the clamping direction without damaging the respective plate. This has an unfavorable effect on the load-bearing capacity in the area of the butt joint at the rear end of the clamping piece. This disadvantage is particularly evident when the ends of the plates are provided with very long hooking claws that are bent at an acute angle.

Gravure cylinders with a plate clamping device are also known, the clamping piece of which can only be pivoted about an axis eccentric with respect to the cylinder axis, so that the front edge of the clamping piece in the clamping direction moves in and out in the radial direction can be swung out. This does, however, facilitate the attachment of a plate-side suspension claw. On the other hand, however, this type of clamping device requires a high level of accuracy in plate manufacture. The reason for this can be seen in the fact that in these known arrangements there is only a very specific position of the clamping piece, in which the outer contour of the clamping piece formed by a rounding with a cylinder radius and the remaining outer contour of the cylinder result in an exact circular shape. If the clamping piece is outside of this position, its outer contour is tilted relative to the circular contour. If the winding plate to be clamped is too long or too short due to the tolerances allowed in the manufacture to achieve the exact position of the clamping piece, there are steps in the area of the front and rear edges of the clamping piece that can lead to shock-like loads, which not only the cylinder bearing is heavily stressed, but also the impression roller and the doctor blade are excited to vibrate. The consequence of this can be paint splashes or streaks on the paper web to be printed, as well as heavy paper stress with a high risk of tearing.

Proceeding from this, it is therefore the object of the present invention to provide a cylinder of the type mentioned in which, despite rough tolerances with regard to the plate length, an exact cylindrical contour of the winding plate to be clamped is achieved over the entire cylinder circumference and in which the clamping process takes the form of a pivoting movement of the clamping piece However, only a very small path is required around the cylinder axis, even when clamping plates with very long hook-in claws bent at an acute angle.

This object is achieved according to the invention in that the clamping piece which can be pivoted about the cylinder axis has a beak edge which can be pivoted about an axis which is offset parallel to the cylinder axis and which cooperates with a clamping member for receiving an associated claw of the winding plate.

This ensures in an advantageous manner that the beak edge of the clamping piece can be pivoted out of the cylinder periphery for hanging in the associated hanging claw about an axis offset parallel to the cylinder axis and can be pivoted about the cylinder axis for subsequent tensioning of the winding plate. The fact that the beak edge can be swiveled out of the cylinder circumference facilitates the insertion of hook-in claws which are bent inwards at an acute angle and therefore not only permits simple plate production, but also ensures high ease of use at the same time. This also applies in an advantageous manner to very long hooking claws which are bent at a very acute angle, which has a positive effect on avoiding bending of the hooking claws and can thus simplify the clamping member assigned to them. With the help of the clamping member, an exact fixation of the plate is possible before the actual clamping process, so that there is no fear of slipping of the plate ends, which can greatly facilitate the insertion process and therefore also has an advantageous effect on the ease of use. Since the beak edge for inserting the associated hooking claw can be extended radially, it is ensured at the same time that the actual clamping process in the form of a pivoting movement around the cylinder axis only ver requires relatively small path, whereby the butt joint remains so small in the area of the edge of the clamping piece opposite the beak edge that no negative influences on the load-bearing capacity are to be feared.

According to a first embodiment, the clamping piece can be designed as a one-piece segment which is pivotably received on a bracket which can be pivoted about the cylinder axis and can be locked here. Such an embodiment can prove to be particularly simple.

Another very particularly preferred embodiment may consist in that the clamping piece has a segment which can be pivoted about the cylinder axis and on which an edge strip with the outer contour corresponding to the cylinder outer contour is arranged so as to be pivotable about an axis offset parallel to the cylinder axis. Here it is possible to extend the beak edge on the edge strip side for hanging in the associated hook-in claw, which facilitates the hook-in process even when the hook-in claw is severely bent, without the need for pivoting space in the region of the segment boundary opposite the beak edge.

In an advantageous further development, this segment can be provided with a seat that starts from the peripheral contour and has a cup-shaped cross-section that is concentric to the axis of rotation of the edge strip, in which a corresponding curvature of the edge strip engages. This ensures that there is practically no gap in the operating position in the area of the butt joint between the edge strip and the segment.

A further expedient measure can consist in that the operating position of the edge strip with respect to the assigned segment can be secured by means of a stop. The stop automatically results in the desired operating position, in which an exactly circular circumferential contour is guaranteed, which has a positive effect on the ease of use.

In a further development of the higher-level measures, the segment on the clamping piece side can comprise approximately half of the cylinder circumference. This ensures that any imprints that may occur in the area of the butt joints between the segment on the clamping piece and the peripheral section that is stationary here lie in the area of the cut or the fold of the printed products cut from the paper web to be printed.

A further advantageous measure can consist in that the segment on the clamping piece side can be supported on the adjacent cylinder section by means of an eccentric shaft in the region of the butt joint opposite the beak edges. These measures result in a simply constructed and easy-to-use clamping device. However, it would also be conceivable to use a closed hose to which a pressure medium is applied as the tensioning element.

In a further advantageous embodiment of the superordinate measures, the segment on the clamping piece side can be galvanized with the respectively adjacent cylinder section in the region of the butt joint opposite the beak edges. This avoids a continuous butt joint, which was expected to have excellent load-bearing capacity ten leaves, so that there is practically no risk of an imprint. This butt joint can expediently run obliquely to an axially parallel surface line, which further increases the load-bearing capacity.

In a further advantageous embodiment of the superordinate measures, the two beak edges can be assigned opposing terminal strips, each of which has a continuous groove in the area of the mutually facing surfaces for receiving a continuous sealing strip. The terminal strips allow an exact fixation of the plate ends before the actual clamping process, so that there is no fear of slipping of the plate ends, which can greatly facilitate the insertion process and therefore has an advantageous effect on the ease of use. The sealing strip held at the same time by the terminal strips not only results in a simple sealing of the slot in the area of the plate ends, but also increases the clamping force applied by the terminal strips when the clamping movement begins. The sealing strip mentioned can expediently be designed as a hose to which a pressure medium can be applied, which can be simply inserted into the assigned channel and brought into clean contact with the channel walls by subsequent pressurization.

In order to prevent the penetration of paint into the slot which results radially outside the sealing strip, it can be expediently sprayed out with a filling consisting of hardening material. For this purpose, the terminal strips can advantageously with an open to the slot to be filled, to an injection nozzle connectable injection channel so that there is a good distribution of the filler.

A further advantageous measure can consist in the winding plate being stepped in the area of its hooking claws. This results in clean, lateral boundaries of the slot to be filled in the circumferential area and thus clean contact surfaces for the filling material. This is limited laterally in the circumferential area by the step-like shoulders of the plate and, despite the rounding of the beak edges, does not run out laterally in the form of an infinitely tapering wedge, which can also have a positive effect on the achievement of an exact cylinder contour.

Further advantageous refinements and preferred developments of the higher-level measures result from the following description of some exemplary embodiments with reference to the drawing in conjunction with the remaining subclaims.

• Figur 1 einen Querschnitt durch einen erfindungsgemäßen Tiefdruckzylinder mit einem zweiteiligen Spannstück,
• Figur 2 eine Draufsicht auf den Zylinder gemäß Figur 1 von der den Schnabelkanten gegenüberliegenden Seite her gesehen,
• Figur 3 einen Ausschnitt aus der Darstellung nach Figur 1 mit dem Bereich des Platteneingriffs in vergrößerter Darstellung und
• Figur 4 einen Querschnitt durch ein weiteres Ausführungsbeispiel mit einem einteiligen Spannstück.

The drawing shows:

• FIG. 1 shows a cross section through an intaglio cylinder according to the invention with a two-part clamping piece,
• FIG. 2 shows a top view of the cylinder according to FIG. 1 seen from the side opposite the beak edges,
• Figure 3 shows a detail of the illustration of Figure 1 with the area of the plate engagement in an enlarged view and
• Figure 4 shows a cross section through a further embodiment with a one-piece clamping piece.

The gravure cylinder shown in FIG. 1, suitable for receiving a winding plate (not shown in more detail), consists of a circumferential section 3 rigidly connected to a central axis 2 by means of webs 1 projecting radially inwards and a pivotally mounted on axis 2 via webs 4 through which axis 2 passes , a circumferential contour corresponding to the circumferential contour of the clamping piece 5, which is adjustable for tensioning the winding plate according to arrow 6 in the circumferential direction about the axis 2. The circumferential section 3 rigidly connected to the axis 2 and the clamping piece 5 each extend over half of the cylinder circumference in the exemplary embodiment shown and are provided on the one hand with beak edges 7 and 8 for hanging the inwardly bent hooking claws of the winding plate, not shown, and have, as on can best be seen from FIG. 2, on the other hand, to achieve a load-bearing transition, toothed ridges 9 which engage in one another in a tooth-like manner. In the exemplary embodiment shown, the toothed strips 9 are arranged parallel to an axially parallel surface line of the cylinder circumference. If the load-bearing capacity should require it, the toothed strips 9 could be slightly inclined with respect to such a surface line. In the area of the cylinder end faces continuous support rings 10 are provided which have a lateral cylinder closure form and through which a doctor cooperating with the cylinder circumference is guided over the joint in the area of the beak edges 7, 8. The support rings 10 protrude beyond the remaining cylinder circumference by an amount corresponding to the thickness of the winding plate indicated at 11 in FIG. The support rings could also simply be designed as twisted bundles. In order to facilitate the hooking in of the associated hooking claw of the winding plate, the clamping edge 8 on the clamping piece side can be swung out in the radial direction, as is indicated in FIG. 1 by dash-dotted lines and is indicated by the arrow 12. For this purpose, the clamping piece 5 is formed in two parts in the illustrated embodiment and includes a pivotable on the cylinder axis 2 segment 13 with an associated beak edge 8 having edge strip 14, which in turn is pivotally mounted about an axis 15 offset parallel to the cylinder axis 2. The ends of the axis 15 formed by a pin or the like can be received on the lateral support rings 10, which then have to be movable about the cylinder axis 2 together with the clamping piece 5. However, it would also be conceivable to mount the edge strip 14 directly on the segment 13 of the clamping piece 5 or on the front side of the mounting tabs by means of a hinge connection or the like. The clamping piece 14, like the segment 13, is circumferentially curved with a radius corresponding to the cylinder radius, so that an exact circular cross section results in the position on which FIG. 1 is based.

In the exemplary embodiment shown, the clamping piece-side segment 13 is on the edge strip side with one in the transverse direction Cut bowl-shaped seat 16 provided, in which a corresponding offset 17 of the skirt 14 engages. The seat 16 and the offset 17 are provided with bearing surfaces that are arched concentrically to the axis 15 and extend to the outer circumference of the cylinder, which enables a large pivoting angle when pivoting the beak edge 8 and results in a stable transition between the segment 13 and the edge strip 14. After the associated hook-in claw has been hooked in, the edge strip 14 is pivoted inward about the axis 15 from the position indicated by dash-dotted lines in FIG. 1 such that its circumferential curvature coincides with the circular circumferential line predetermined by the cylinder circumference. The plate can then be tensioned by pivoting the entire clamping piece 5 about the cylinder axis 2. In the exemplary embodiment shown, the operating position of the edge strip 14 is defined by a stop strip 18 which is fastened here to the edge strip 14 and, in the operating position, bears against an assigned stop surface of the segment 13. The pivoting movement of the edge strip 14 about the assigned axis 15 can be carried out by means of a toggle lever drive (not shown here in greater detail) or preferably by means of an eccentric shaft. The same applies to the pivoting movement of the segment 13 and thus the entire clamping piece 5 about the cylinder axis 2. In the exemplary embodiment shown, the clamping element for moving the clamping piece 5 is in a butt joint formed by the toothed strips 9 between the segment 13 on the clamping piece side and one for with respect to the cylinder axis 2 stationary circumferential section 3 belonging to segment 19 provided channel 20 arranged, operable from the side eccentric shaft 21 which bridges the butt joint and on the one hand on segment 13 and on the other hand is supported on the segment 19. Instead of this, a hose could also be provided as a tensioning element, which could be acted upon with a pressure medium, for example with hydraulic fluid, via a lateral valve, not shown here, which could be passed through a lateral tensioning ring 10. When the hose 21 is pressurized accordingly, the hose 21 expands and displaces the tensioning piece 5 in the direction of the arrow 6.

For non-slip fixing of the hooking claws on the beak edges 7 and 8, clamping members attached to them are assigned, here in the form of continuous, pivotably mounted clamping strips 22. The terminal strips 22 are adjustable in the illustrated embodiment by means of an associated eccentric shaft 23. When preparing a cylinder, the winding plate is first fixed to the beak edge 7 of the stationary peripheral section with a hooking claw, then placed around the cylinder circumference and then firmly clamped to the beak edge 8 of the clamping piece 5 by means of the associated clamping strip 22. This clamping of the plate ends ensures a non-slip position, so that the plate does not have to be additionally secured during the clamping process. Subsequently, the edge strip 14 having the beak edge 8 is pivoted back until the stop strip 18 runs onto the associated contact surface. The actual clamping process then takes place by pivoting the entire clamping piece 5 about the cylinder axis 2, an exact circular contour being maintained regardless of the required clamping angle until the clamping position is reached.

After tensioning the plate in the area of Slit 24 remaining at the plate ends is sealed and sprayed with a filling consisting of hardening material. For this purpose, the clamping strips 22, as can best be seen in FIG. 3, are provided with grooves 25 running over their entire length, which form a channel in which a sealing strip 26 can be inserted. The sealing strip 26 can be inserted loosely before the tensioning process is carried out. As a result of the tensioning process, the channel assigned to the sealing strip 26 narrows, as a result of which the sealing strip 26 is pressed against the channel walls. The sealing strip 26 can be formed by a sealing cord made of elastic material or by a so-called tear strip, which is provided with a tear insert formed by a wire or the like. In the exemplary embodiment shown, the sealing strip 26 is to be designed as a closed hose which can be acted upon by a pressure medium via a valve on the side, which is accessible in the region of a lateral support ring 10. The pressurization exerted by the clamping strips 22 is increased by such pressurization and by the additional pressure increase resulting during the clamping process.

For uniform distribution of the filling 27 to be injected into the slot 24, the clamping strips 22 are provided radially outside of the grooves 25 with further grooves 28 which form a continuous distribution channel which can be acted upon with filling material via a lateral injection nozzle. The filling material can be injected in such a way that the radially outer boundary of the filling 27 is formed by a fillet, the depth of which is chosen such that the color collected therein does not come close to the paper passing over it enough. In the illustrated embodiment, the slot 24 is completely filled. For this purpose, use is made of a shaped bar 29 provided with a bearing surface, the curvature of which corresponds to the curvature of the cylinder covered with the plate, which is placed on the occupied cylinder in the region of the slot 24. The slot 24 is thus closed by the form bar 29, the sealing strip 26, the side support rings 10 and the beak edges 7 and 8, so that the filling 27 can be pressed in with high pressure. To accomplish a simple lateral limitation of the filling 27 in the area of the outer circumference of the winding plate, the latter is stepped in the area of the hooking claws 30. For this purpose, the winding plate simply consists of a continuous support plate 31 and a coating 32 containing an engraving, which ends in the region of the hanging claws.

Instead of a two-part clamping piece provided with a pivotable edge strip, a one-piece clamping piece could also be provided, as shown in FIG. The basic structure of the arrangement according to FIG. 4 corresponds to the arrangement according to FIG. 1. The same reference numerals are therefore used for the same parts. The one-piece clamping piece 5 is in this case formed by a segment 33 which extends over a cylinder half and to which the associated beak edge 8 is formed and which is received on a bracket 35 which can be pivoted about an axis 34 which is offset parallel to the cylinder axis 2 and is pivotable about the cylinder axis 2. The segment 33 can be locked in the operating position with respect to the block 35. To hook in the associated hook-in claw, the entire segment 33 is pivoted about the eccentric axis 34 in accordance with arrow 12, as a result of which the beak edge 8 emerges from the cylinder circumference occurs. To tension the plate, the entire segment 33 is pivoted about the cylinder axis 2 according to arrow 6. The further construction of the cylinder according to FIG. 4 can correspond to the arrangement according to FIG. 1, so that reference can be made here to avoid repetitions.

Claims (11)

1. Cylinder for rotogravure printing presses with a device for tensioning winding plates (11) which puffs a clamping piece (5) which can be pivoted about the cylinder axis with an outer contour corresponding to the cylinder outer contour, characterized in that the clamping piece (5) which can be pivoted about the cylinder axis has a one Axis (15 or 34) which is offset parallel to the cylinder axis and has pivotable beak edge (8) which interacts with a clamping member (22) for receiving an associated hook-in claw (30) of the winding plate (11). 2. Cylinder according to claim 1, characterized in that the clamping piece (5) as a one-piece, on a pivotable about the cylinder axis (2) bracket (35) pivotally received, lockable segment (33) is formed, to which the associated beak edge ( 8) is molded. 3. Cylinder according to claim 1, characterized in that the clamping piece (5) has a pivotable about the cylinder axis segment (13) on which the associated beak edge (8) having edge strip (14) with the outer contour of the cylinder corresponding outer contour is arranged so as to be pivotable about an axis (15) offset parallel to the cylinder axis (2), the segment (13) having a seat (16) with a shell-shaped cross-section that starts from the peripheral contour and is concentric to the axis (15) of the edge strip (14) ) is provided, in which a correspondingly curved offset (17) of the edge strip (14) engages, the operating position of which is secured with respect to the assigned segment (13) by means of a stop (18). 4. Cylinder according to one of the preceding claims, characterized by a central cylinder axis (2) with a rigidly connected thereto, each comprising a cylinder half, a beak edge (7) with respect to the cylinder axis (2) stationary segment (19) and a pivotable thereon arranged, each comprising a cylinder half segment (13 and 33), and by continuous support rings (10) provided in the area of the cylinder end faces. 5. Cylinder according to one of the preceding claims, characterized in that the clamping piece (5), which preferably comprises a cylinder half, by means of an eccentric shaft (21) in the region of the butt joint opposite the beak edges (7 or 8) on the respectively adjacent one, with respect to the cylinder axis (2 ) stationary cylinder section (3) can be supported. 6. Cylinder according to one of the preceding claims., Characterized in that the clamping piece (5) in the area of the beak edges (7 or 8) opposite lying, preferably obliquely to an axially parallel surface line butt joint is galvanized with the adjacent cylinder section (3) which is stationary with respect to the cylinder axis (2). 7. Cylinder according to one of the preceding claims, characterized in that the two beak edges (7 and 8) opposing clamping members are preferably in the form of continuous clamping strips (22) assigned, each in the area of the facing surfaces a continuous groove (25) to form a channel assigned to a sealing strip (26) which is preferably designed as a hose to which a pressure medium can be applied. 8. Cylinder according to claim 7, characterized in that the radially outside of the sealing strip (26) resulting slot (24) can be filled with a filling consisting of hardening material (27), which preferably consists of a by means of a molded oil bar (29 ) to the cylinder surface coverable slot (24) consists of injectable material, and that the terminal strip or terminal strips (22) are provided with continuous grooves (28) to form a slot (24) to be filled, preferably continuous, connectable to an injection nozzle are. 9. Cylinder according to one of the preceding claims, characterized in that the winding plate (11) is stepped in the region of the lateral boundary of the filling (27). 10. Cylinder according to one of the preceding claims, characterized by a fillet having a fillet in the region of the radially outer circumference (27) of the slot (24).

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